Flow batteries are an old invention that can be used in stationary applications
where weight and space is not critical. In the future they will be used as a grid balance of intermitent enregy sorces like solar and wind energy.
In Sweden, a lot of small family houses have some kilowatt solar on their roofs, that could benefit from a flowbattery of 10kWh.
Our flow batteries works with an ion fluid made out of zink and iron.
As long as there are some concentration of ions left, the battery will
produce energy. There are no theoretical limit for the numbers of
charging and dischargings. The battery is made to  last for 20 years.